Genome-Wide Analysis of MIKCC-Type MADS-Box Genes in Grapevine

DIAZ-RIQUELME, J; LIJAVETZKY, D; MARTINEZ-ZAPATER, JM; CARMONA, MJ

Adelaide

Simposio; Eighth International Symposium on Grapevine Physiology and Biotechnology; 2008

Australian Society of Viticulture and Oenology

Background and AimsMIKCC-type MADS-box genes encode transcription factors that play crucial roles in plant growth and development. Analysis of the grapevine genome revealed up to 38 MIKCC-type genes. We report here a complete analysis of this gene family regarding their phylogenetic relationships with homologous genes identified in other sequenced dicot genomes, their genome location, and gene structure and expression.Methods and ResultsGrapevine MIKCC-type MADS-box genes cluster with their Arabidopsis thaliana and Populus trichocarpa counterparts in 13 subfamilies. The lack of recent whole genome duplications in grapevine helps to assign the gene diversification processes observed within each subfamily to either an ancestral poliploidization event predating divergence of those three species or to later duplication events within each lineage. Quantitative RT-PCR expression profiles of MIKCC-type genes in vegetative and reproductive organs show conserved expression domains for specific subfamilies but also reflect characteristic features of grapevine development. Furthermore, expression analyses along latent buds development reveal common features previously described in other plant system as well as the possibility of new roles for members of some subfamilies during flowering transition.ConclusionsOver a general pattern of conservation in the number of gene subfamilies and their expression patterns, variations in gene number and expression are found in specific subfamilies suggesting the existence of subfunctionalization / neofunctionalization processes. Some of these variations in expression profiles reflect characteristic features of grapevine development. For example, the expression of AP1/FUL subfamily in tendril and the detection of SEP and AP3/PI subfamily members along fruit development and ripening; that could reflect the developmental differences between dry silique fruits and fleshy berry fruits.Significance of StudyThe analysis of MIKCC-type genes in grapevine helps understanding the origin of gene diversification within each subfamily and provides the basis for functional analyses to uncover the biological role of these MADS-box genes in grapevine development.